If you want to be a better editor of others’ work, purge yourself of rookie mistakes.

Know the difference between copy editing and editing for substance. Don’t assume you are meant to do both. Key considerations:

1. How many approval cycles has this been through?

2. What gatekeepers have already signed off on it?

3. How close is the deadline?

Copy close to the end of its development process needs a light hand. If you introduce questions or suggestions, you are inviting error and undoing the work of a team that was chosen for its expertise.

In this situation, you are a copy editor. So you must think of yourself as a surgeon, not a psychologist or innovator. That means removing just the tumor while leaving healthy organs intact.

Never trust. Sorry, but that’s how it is. I’m an optimist and I believe that most people are aiming for goodness. But when it comes to copy editing, never trust yourself or others. Always look it up. Look it up, look it up, look it up. Can’t say this enough.

Plan on learning grammar, punctuation and style for the rest of your life. You’re never done. There’s always more. Here are a couple of examples of what I find many people aren’t clear on:

Who is the audience? What do they already know (so you won’t repeat words that waste their time)? What are their PDAs (problems, decisions, actions)? Use in-house and online resources to better understand who is in your audience, list the different job titles or skill sets within that audience and filter content that will help them solve problems, make decisions and move them forward toward their goals as they define them. Dig for content such that you answer the “why,” not just the “how.”

2. How can we drive long-term business goals?

Even if you are allowed to be creative, you still need to color inside the lines. In other words, know the business parameters that will keep you from going off on a tangent that won't advance your company's business goals.

What indirect takeaways should readers be left with? Have a list of adjectives and messages for each of these: industry, company, product, competition.

What are my company's top three overarching business goals? Where does your company want to be three years from now? (Not this year, not next year, but three to five years out.) Your answer has to be more specific than "drive sales." For example, it might be "shift from primarily commercial to primarily residential," "open new markets in India," "grow expertise in mobile technologies."

3. What's lurking below a messy surface?

If you hit a place in the text where a teacher might mark in red pen “awkward,” don’t rewrite it. Get up and talk to the writer. Ask why it was done that way. Most of the time, the writer had a good reason for it. Draw on your own editing and writing experience to get at the root cause or accurately write around a wrinkle. Conversation is best.

4. What matters most? Why?

Why does this matter? So what? What’s in it for the reader? What’s counterintuitive about this content? What decision will this help the reader make? Where’s the surprise?

If you can’t find the answers to these questions, you must do research or ask the writer to do research. You aren’t ready to write if you can’t answer the above.

5. What's the proper tone?

Does the tone match the platform? I give entire classes on tone. But one way (among many) to begin addressing that is to improve the quality of your verbs. If you want to emphasize policy, minimize discussion, or blend into the wallpaper for legal reasons, use a lot of Latinate words. If you want to build relationships, use Anglo-Saxon words.

6. What works best for the media? Should we change media? What audio/visual material is available? Would either of these be more effective than text? Who owns the rights to the photos/videos/audio?

What sidebars could be more immediately illustrative than text? Should we add complementary materials? What related questions does the topic raise that should be addressed but shouldn’t be confused with the main point? Should those be pulled out for sidebars?

7. OK, I fibbed a little. There's more than seven. Here's a grab bag of questions related to content selection.

Do we need numbers? Imagery? Both? In what proportions?

What kind of attention span can I expect? Is this a captive audience or a voluntary audience? Is the audience bound to comply, or do we need to persuade?

Do we need to keep it strategic and focused on business goals? Or should it be about tactics and execution? Should we compare and contrast? Do the math?

Do we need a narrative style with a character overcoming obstacles in pursuit of a goal? Or a three-line synopsis geared toward the recipient’s immediate need for decision-making or action-taking? Would it be better to boil down three bullets on a slide?

Should we provide a lot of background rationale even for what are thought to be less desirable options? Is this document primarily archival?

Will this be for a broad or narrow audience? If both, is the material for the broad audience at the top and the narrow audience at the bottom?

A former AP news reporter, Lauren Edwards has been customizing editing and writing workshops for PR professionals and engineers at companies including Intel, Yahoo and Google for the past 10 years. This post first appeared on Ragan.com in 2010.